Can childhood sexual abuse cause porn issues as an adult?

I’m about to get married. My fiancé was molested when he was very young by his grandparent. The other grandparent defended it and the whole family did nothing and swept it under the rug. Our whole relationship he has been amazing, but our one issue is porn. He watches it behind my back and in public restrooms when it’s empty, as I’m always by him when he’s home. And he lies to me about it. He just told me he thinks it could be from what happened to him and he thinks about suicide when he thinks about what he’s doing and what happened to him. We are looking into getting him the counseling his family never gave him but I am at loss.